A near-unity efficiency source of entangled guided waves

TL;DR

This paper demonstrates a highly efficient method for generating entangled light in the IR/THz range using surface phonon polaritons, significantly improving emission rates over free space and enabling new quantum light source designs.

Contribution

It introduces a novel approach leveraging surface phonon polaritons to create near-unity efficiency entangled photon sources in the IR/THz spectrum.

Findings

Two-photon emission can occur on nanosecond timescales.

Emission rates are nearly two orders of magnitude faster than in free space.

Potential for broad-spectrum entangled photon sources.

Abstract

Surface phonon polaritons are hybrid modes of photons and optical phonons that can propagate on the surface of a polar dielectric. In this work, we show that the precise combination of confinement and bandwidth offered by surface phonon polaritons allows for the ability to create highly efficient sources of entangled light in the IR/THz. Specifically, phonon polaritons can cause emitters to preferentially decay by the emission of pairs of surface phonon polaritons, instead of the previously dominant single-photon emission. We show that such two-photon emission processes can occur on nanosecond time-scales and can be nearly two orders of magnitude faster than competing single-photon transitions, as opposed to being as much as eight to ten orders of magnitude slower in free space. Our results suggest a fundamentally new design strategy for quantum light sources in the IR/THz: ones that prefer to emit a relatively broad spectrum of entangled photons, potentially allowing for new sources of both single and multiple photons.